OBJECTIVES: The objectives of this research are: (1) to determine whether activity and brain metabolism (i.e. respiration and nutrient uptake) are affected by African trypanosomiasis; (2) to examine the possibility that observed changes in activity and brain metabolism might be caused either by aberrant turnover of noradrenaline and serotonin or by accumulations of trypanosome metabolites of tyrosine and tryptophan; and (3) to devise a means of pharmacologic intervention designed to improve brain nutrition and correct behavioral changes by restoring normal levels of noradrenaline and serotonin and inhibiting synthesis of the toxic trypanosome metabolites. METHODS: Will include: (1) quantitation of activity changes in infected voles with an electronic activity monitor; (2) spectrofluorometric measurements of noradrenaline and serotonin in whole brain, choroid plexus, and microvessels of infected vs. normal voles; (3) measurement of selected trypanosome metabolites of tryptophan and tyrosine in whole brain; (4) measurement of brain activities of the aminotransferases and hydroxylases specific for tyrosin and tryptophan; and (5) measurement of respiration and uptake of glucose, tryosine, and tryptophan in brain slices and microvessels from infected vs. normal voles, and from normal voles in the presence of the trypanosome metabolites.